Picolinic N-oxide Research Articles

Structure of pentakis(2-picoline N-oxide)cobalt(II) perchlorate, [Co(C6H7NO)5] (ClO4)2

Structure of pentakis(2-picoline N-oxide)cobalt(II) perchlorate, [Co(C6H7NO)5] (ClO4)2

The mechanism of the reactions of 2- and 4-alkylpyridine N-oxides with acetic anhydride

The reaction of 2-benzylpyridine, 2- and 4-picoline N-oxides with acetic anhydride has been investigated by means of kinetic and 18O-tracer experiments. The large kinetic isotope effects found for all these reactions suggest the proton-removal step to be rate-determining. The uneven distribution of 18O between the alcohol and carbonyl O- atoms of the esters formed appears to result from the confonnational preference of the “anhydrobase” intermediates. The slight effect of salts and substituents on the rate are also discussed.

Co-ordination chemistry of scandium. Part III. Complexes of scandium(III) perchlorate with uni- and bi-dentate oxygen donor ligands

Complexes of the type [ScL6](ClO4)3{L = dimethyl sulphoxide, NN-dimethylformamide, pyridine N-oxide, 2-, 3-, and 4-picoline N-oxides, ½(2,2′-bipyridyl 1,1′-dioxide), ½[1,2-bis-(diphenylphosphinylethane)], ½[1,2-bis-(diphenylarsinyl)ethane] have been isolated. With triphenylphosphine oxide, ScL4(ClO4)3 is obtained. Complexes have been characterized by i.r. and Raman spectroscopy and conductance measurements. I.r. spectral data indicate distortion of the [ScL6]3+ cations from Oh symmetry, and co-ordination of the perchlorate ion in the triphenylphosphine oxide complex.

CIDNP in the reaction of 2-picoline N-oxide with acetic anhydride

CIDNP in the reaction of 2-picoline N-oxide with acetic anhydride

Co-ordination chemistry of scandium. Part II. Scandium(III) thiocyanate and some complexes with unidentate oxygen donor ligands

Attempts to isolate scandium(III) thiocyanate resulted in a white, non-stoicheiometric hydrated species. The yellow colour usually associated with ethereal extracts of scandium thiocyanate is suggested to arise from acid hydrolysis and oxidative decomposition of the anion. Complexes of the type Sc(NCS)3L3(L = pyridine N-oxide; 2-, 3-, and 4-picoline N-oxides; 2,6-lutidine N-oxide; triphenylphosphine oxide; triphenylarsine oxide; dimethyl sulphoxide; and NN-dimethylformamide) have been isolated.

Reactions of trichloroacetyl chloride with 2-picoline N-oxide and pyridylcarbinols

Reactions of trichloroacetyl chloride with 2-picoline N-oxide and pyridylcarbinols

Uneven distribution of 18O in the resulting esters formed in the reaction of 2-picoline, 2,6-lutidine and quinaldine N-oxide with acetic anhydride

Uneven distribution of 18O in the resulting esters formed in the reaction of 2-picoline, 2,6-lutidine and quinaldine N-oxide with acetic anhydride

Reaction of 4-picoline N-oxide with acetic anhydride. Trapping of the cationic intermediate

Reaction of 4-picoline N-oxide with acetic anhydride. Trapping of the cationic intermediate

Preparation of aldehyde derivatives from picoline N-oxides.

Preparation of aldehyde derivatives from picoline N-oxides.

Electron spin resonance spectra of the radical anions of pyridine and related nitrogen heterocyclics

The E.S.R. spectra of the radical anions of pyridine, 4-picoline, 3,5-lutidine, 2,6-lutidine, pyrazine, pyrimidine, pyridine N-oxide, 4-picoline N-oxide and 2,6-lutidine N-oxide have been observed in liquid ammonia. The data for pyridine, pyrazine and pyrimidine can be combined to evaluate Q N N = +27·3, Q CN N = -1·7 and Q H = -24·5 gauss independently of molecular orbital spin densities. Good agreement is found for the observed coupling constants for the N-heterocyclics and McLachlan's theory with methyl group coupling consistent with both Levy's hyperconjugation equations and with Q CH3 eff. = 25·7 gauss. The coupling constants for the N-oxides are in satisfactory agreement with an arbitrary set of molecular orbital parameters.

The Reaction of 2-Picoline N-Oxide with Substituted Acetic Anhydrides

The Reaction of 2-Picoline N-Oxide with Substituted Acetic Anhydrides

Substituted Pyridine N-Oxide Complexes of Copper(II) Halides. II. Magnetic Properties of Complexes with 3-Picoline N-Oxide, 2,6-Lutidine N-Oxide, and 2,4,6-Collidine N-Oxide

Substituted Pyridine N-Oxide Complexes of Copper(II) Halides. II. Magnetic Properties of Complexes with 3-Picoline N-Oxide, 2,6-Lutidine N-Oxide, and 2,4,6-Collidine N-Oxide

Copper(II) Halide Complexes with Substituted Pyridine N-Oxides

Abstract Pyridine N-oxide copper(II) chloride, the structure of which has recently been elucidated by X-ray analysis [J. C. Morrow and H. L. Schäfer, private communication], has a subnormal magnetic moment (0.85 b.m. [J. V.Quagliano, J. Fujita, G. Franz, D. J. Phillips, J. A. Walmsley and S. Y. Tyree (J. Am. Chem. Soc., 83, 3770 (1961)]). It consists of a binuclear molecule [Cu(C5H5NO)Cl2]2 in which copper atoms are bridged in pairs by two oxygen atoms. In this work, copper(II) complexes with the empirical formulae of CuX2L, CuX2L2 and CuX2LY (X=Cl, Br;L=pyridine N-oxide, 3-picoline N-oxide, 4-picoline N-oxide, 4-chloropyridine N-oxide, 2,4-lutidine N-oxide, 2,4,6-collidine N-oxide, 4-nitroquinoline N-oxide; Y=N,N′-dimethylformamide, dimethylsulfoxide) have been prepared, and magnetic and spectral studies of these complexes have been made. The room-temperature magnetic susceptibilities of CuX2L complexes have been found to be correlated with the pKa (acid-dissociation constant) values of the attached N-oxides. The absorption band in the 735–900 mμ region (the so-called copper band) in the solid-state reflectance spectra of CuX2L complexes has been found to shift towards a lower frequency as the ligand field strength decreases, and a good parallelism between the frequencies and the magnetic moments has been observed. The effect of the attached ligand on the magnetic interaction has been discussed in terms of the electronic effect of the substituent on the pyridine ring. The infrared spectral data on the N–O stretching frequency indicate the absence of Cu–O–Cu linkage in the CuX2L2 complexes with normal magnetic moments.

The Reactions of 2- and 4-Picoline N-Oxide with Phenylacetic Anhydride1

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Reactions of 2- and 4-Picoline N-Oxide with Phenylacetic Anhydride1Theodore Cohen and John H. FagerCite this: J. Am. Chem. Soc. 1965, 87, 24, 5701–5710Publication Date (Print):December 1, 1965Publication History Published online1 May 2002Published inissue 1 December 1965https://doi.org/10.1021/ja00952a031RIGHTS & PERMISSIONSArticle Views273Altmetric-Citations21LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Aromatic N-Oxides. V. The Reaction of 4-Picoline N-Oxide with Various Anhydrides1,2

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAromatic N-Oxides. V. The Reaction of 4-Picoline N-Oxide with Various Anhydrides1,2Vincent J. Traynelis and Ann Immaculata Gallagher Sr.Cite this: J. Am. Chem. Soc. 1965, 87, 24, 5710–5715Publication Date (Print):December 1, 1965Publication History Published online1 May 2002Published inissue 1 December 1965https://doi.org/10.1021/ja00952a032RIGHTS & PERMISSIONSArticle Views114Altmetric-Citations18LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (762 KB) Get e-Alerts Get e-Alerts

Oxygen transfer reactions of aromatic amine N-oxides

OXYGEN TRANSFE!R EACTIONS OF AROMATIC AMINE N-OXIDES T. Koenig Department of Chemistry, University of Oregon Eugene, Oregon (deceived 3 June 19651 ti revbed form 16 July 1965) Two reports (1,2) have recently appeared dealing with the reactions of aromatic amine N-oxides with phenylacetic anhydrides. We have also independently observed this reaction which stoichiometrically involves two equivalents of the N-oxide to one of the anhydride and which gives two equivalents of the corresponding amine and one each of carbon dioxide, phenylacetic acid snd benzaldehyde as products. The reaction proceeds readily with both pyridine N-oxide and &picoline N-oxide but only to a minor extent with 2-picoline N-oxide (3). Benza.ldehyde and carbon dioxide were formed in high yields (greater than 60s) in both of the former cases. We have measured the kinetic dependence of the reaction of kpicoline N-oxide with phenylacetic anhydride in acetonitrile with varying amounts of added phenylacetic acid. The data are summarized in Table I. The rates were followed by the decrease in infrared carbonyl adsorption of the anhydride. Linear rate plots for 60s reaction are obtained using the integrated rate expression corresponding to eq. 1.

By-products in the reaction of 2-picoline N-oxide with acetic anhydride

In support of earlier work by Okuda, the apparently homogeneous product from reaction of 2-picoline N-oxide with acetic anhydride, described in the literature as 2-acetoxymethylpyridine, is shown to consist of about 66% of this substance, together with approximately equal amounts of 3-acetoxy-2-picoline and 5-acetoxy-2-picoline. The N.M.R. and mass spectra of these isomeric acetoxy compounds are discussed.

Rearrangement of tertiary amine oxides—XI : Solvent effects on the reactions of 2- and 4-picoline N-oxides with acetic anhydride

The reactions of 2- and 4-picoline N-oxides with acetic anhydride uniformly labelled with 18O have been studied in three different solvents and the products subjectd to 18O analyses. With 2-picoline N-oxide, the change of solvent did not effect the 18O distribution of the resulting main product, 2-acetoxymethylpyridine. The reaction proceeds via “radical cage process”, similar to the previous experiment with no solvent. In the case of 4-picoline N-oxide, the reaction in the sovlents appears to be different, the concentration of 18O in the resulting ester mixture, i.e., 3-acetoyx-4-methylpyridine and 4-acetoxymethylpyridine approaching the value that is expected from the radical pair process. The effect of solvent and the nature of these rearrangements are briefly discussed.

Rearrangement of tertiary amine oxides—X : The mechanism of the reaction of 4-picoline N-oxide with n-butyric anhdyride

The reaction of 4-picoline N-oxide with n-butyric anhydride has been investigated using 18O as tracer. The main products, a mixture of 3-butyroxy-4-methylpyridine and 4-butyroxy-methylpyridine, obtained by the reaction of 4-picoline N-oxides and n-butyric anhydride uniformly labeled by 18O have been subjected to 18O-analysis. When no solvent is used, the 18O concentration of the ester mixture is nearly identical with that expected when the reaction proceeds via an intermolecular process. Whereas, when xylene is used as solvent, the concentration of 18O of the ester mixture becomes quite small and approaches the value expected from the radical cage mechanism. However, n-butyroxy radicals undergo a radical transfer reaction with n-butyric acid, while the 18O concentration of the ester mixture decreases substantially when DPPH is added to the reaction mixture of 4-picoline N-oxide and n-butyric anhydride. These observations and others, support the mechanism of the reaction of 4-picoline N-oxide and n-butyric anhydride as a combination of an intermolecular heterolytic process, an intermolecular homolytic reaction and a radical cage path, and the ratio of these processes changes with a change of solvent.

Rearrangement of tertiary amine N-oxide—XII : The mechanism of the reaction of 3-picoline N-oxide with acetic anhydride

The reaction of 3-picoline N-oxide with acetic anhydride to give 2-acetoxy-3-methylpyridine and 2-acetoxy-5-methylpyridine has been investigated using 18O as tracer. The 18O concentration of the ester mixture was found to be of an average value of one natural and three oxygens with excess 18O when the N-oxide reacted with an equimolar amount of uniformly 18O-labelled acetic anhydride. When 18O-labelled acetic anhydride was used in excess, the 18O value of both the etheral and carbonyl oxygens of the ester mixture attained an average value of all the oxygens of the reaction mixture. These results and others strongly suggest an intermolecular ionic process for this reaction.